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Species richness
About: Species richness is a research topic. Over the lifetime, 61672 publications have been published within this topic receiving 2183796 citations.
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TL;DR: It is suggested that increased species diversity of plant litter is less important than that of live plants for determining ecosystem properties and perceived relationships between biodiversity and ecosystem function may be of diminished significance when the ecological importance of plant littered is fully appreciated.
Abstract: There has been a rapidly increasing recent interest in the effects of biological diversity on ecosystem properties, and while some studies have recently concluded that biodiversity improves ecosystem function, these views are based almost entirely on experiments in which species richness of live plants has been varied over all the species diversity treatments. However, most net ecosystem primary productivity eventually enters the decomposition subsystem as plant litter where it has important afterlife effects. Weconducted a field experiment in which litter from 32 plant species (i.e. effects. We conducted a field experiment in which litter from 32 plant species (i.e. eight species of each of four plant functional groups with contrasting litter quality) was collected and placed into litter-bags so that each litter-bag contained between one and eight species; the species which were included in the multiple (>2) species litter-bags were randomly selected. This litter diversity gradient was created within each functional group and across some functional groups. We found large non-additive effects of mixing litter from different species on litter decomposition rates, litter nitrogen contents, rates of nitrogen release from litter and the active microbial biomass present on the litter. The patterns and directions of these non-additive effects were dependent upon both plant functional group and time of harvest, and these effects could be predicted in some instances by the initial litter nitrogen content and the degree of variability of nitrogen content of the component species in the litter-bag. There was no relationship between litter-bag species richness and any of the response variables that we considered, at least between two and eight species. Within plant functional groups our results provide some support for the species redundancy and idiosyncratic hypotheses about how biodiversity alters ecosystem function, but no support for the ecosystem rivet hypothesis or the view that species richness of plant litter is important for ecosystem function. We suggest that increased species diversity of plant litter is less important than that of live plants for determining ecosystem properties (and provide possible reasons for this) and conclude that perceived relationships between biodiversity and ecosystem function may be of diminished significance when the ecological importance of plant litter is fully appreciated.
677 citations
Academy of Sciences of the Czech Republic1, Stellenbosch University2, Charles University in Prague3, Canterbury of New Zealand4, University of Tennessee5, University of Fribourg6, Zoological Society of London7, University College London8, Williams College9, Durham University10, University of Vienna11, South African National Parks12, International Union for Conservation of Nature and Natural Resources13, Free University of Berlin14, Leibniz Association15, Helmholtz Centre for Environmental Research - UFZ16, Martin Luther University of Halle-Wittenberg17, Czech University of Life Sciences Prague18, United States Forest Service19, University of Toronto20, University of Rhode Island21, University of Concepción22, Taizhou University23, University of Konstanz24, University of Seville25, Spanish National Research Council26, University of Pretoria27
TL;DR: Improved international cooperation is crucial to reduce the impacts of invasive alien species on biodiversity, ecosystem services, and human livelihoods, as synergies with other global changes are exacerbating current invasions and facilitating new ones, thereby escalating the extent and impacts of invaders.
Abstract: Biological invasions are a global consequence of an increasingly connected world and the rise in human population size The numbers of invasive alien species – the subset of alien species that spread widely in areas where they are not native, affecting the environment or human livelihoods – are increasing Synergies with other global changes are exacerbating current invasions and facilitating new ones, thereby escalating the extent and impacts of invaders Invasions have complex and often immense long‐term direct and indirect impacts In many cases, such impacts become apparent or problematic only when invaders are well established and have large ranges Invasive alien species break down biogeographic realms, affect native species richness and abundance, increase the risk of native species extinction, affect the genetic composition of native populations, change native animal behaviour, alter phylogenetic diversity across communities, and modify trophic networks Many invasive alien species also change ecosystem functioning and the delivery of ecosystem services by altering nutrient and contaminant cycling, hydrology, habitat structure, and disturbance regimes These biodiversity and ecosystem impacts are accelerating and will increase further in the future Scientific evidence has identified policy strategies to reduce future invasions, but these strategies are often insufficiently implemented For some nations, notably Australia and New Zealand, biosecurity has become a national priority There have been long‐term successes, such as eradication of rats and cats on increasingly large islands and biological control of weeds across continental areas However, in many countries, invasions receive little attention Improved international cooperation is crucial to reduce the impacts of invasive alien species on biodiversity, ecosystem services, and human livelihoods Countries can strengthen their biosecurity regulations to implement and enforce more effective management strategies that should also address other global changes that interact with invasions
677 citations
TL;DR: It is suggested that the critical threshold for N-induced species loss to mature Eurasian grasslands is below 1.75gNm � 2 yr � 1, and that changes in aboveground biomass, species richness, and plant functional group composition to both mature and degraded ecosystems saturate at N addition rates of approximately 10.5 gNm� 2 yr� 1.
Abstract: Nitrogen (N) deposition is widely considered an environmental problem that leads to biodiversity loss and reduced ecosystem resilience; but, N fertilization has also been used as a management tool for enhancing primary production and ground cover, thereby promoting the restoration of degraded lands. However, empirical evaluation of these contrasting impacts is lacking. We tested the dual effects of N enrichment on biodiversity and ecosystem functioning at different organizational levels (i.e., plant species, functional groups, and community) by adding N at 0, 1.75, 5.25, 10.5, 17.5, and 28.0gNm � 2 yr � 1 for four years in two contrasting field sites in Inner Mongolia: an undisturbed mature grassland and a nearby degraded grassland of the same type. N addition had both quantitatively and qualitatively different effects on the two communities. In the mature community, N addition led to a large reduction in species richness, accompanied by increased dominance of early successional annuals and loss of perennial grasses and forbs at all N input rates. In the degraded community, however, N addition increased the productivity and dominance of perennial rhizomatous grasses, with only a slight reduction in species richness and no significant change in annual abundance. The mature grassland was much more sensitive to N-induced changes in community structure, likely as a result of higher soil moisture accentuating limitation by N alone. Our findings suggest that the critical threshold for N-induced species loss to mature Eurasian grasslands is below 1.75gNm � 2 yr � 1 , and that changes in aboveground biomass, species richness, and plant functional group composition to both mature and degraded ecosystems saturate at N addition rates of approximately 10.5gNm � 2 yr � 1 . This work highlights the tradeoffs that exist in assessing the total impact of N deposition on ecosystem function.
675 citations
TL;DR: In this paper, the authors examined the spatial distributions of trees in North America to determine which characteristics of the environment are most closely related to the species richness of different regions and found that topography and proximity to the sea are significantly related to residual variation, whereas seasonal climatic variability and glacial history are not.
Abstract: Biologists have long recognized the striking geographical variability of species richness1. A primary goal of contemporary ecology is to identify the factors responsible for this variability2. We have examined the spatial distributions of trees in North America to determine which characteristics of the environment are most closely related to the species richness of different regions. Realized annual evapotranspiration, which is correlated with primary production and is therefore a measure of available energy, statistically explains 76% of the variation in species richness. Topography and proximity to the sea are significantly related to the residual variation, whereas seasonal climatic variability and glacial history are not. Tree richness in Great Britain and Ireland can be accurately predicted from these North American patterns. Our data are best explained by the hypothesis that contemporary available energy limits species richness3,4.
671 citations
Austrian Academy of Sciences1, University of Vienna2, Ilia State University3, Spanish National Research Council4, University of Innsbruck5, University of Granada6, Mediterranean Agronomic Institute of Chania7, Norwegian University of Science and Technology8, Slovak Academy of Sciences9, Russian Academy of Sciences10, University of Molise11, Babeș-Bolyai University12, University of Pavia13, University of Geneva14, University of Parma15, University of Lausanne16
TL;DR: Recent changes in vascular plant species richness observed in a standardized monitoring network across Europe’s major mountain ranges are presented and indicate that high-altitude species, and in particular the rich endemic alpine flora of many Mediterranean mountain ranges, will come under increasing pressure in the predicted warmer and drier climates in this region.
Abstract: In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.
669 citations